The subject invention relates to amidation reaction products and their use in coating compositions. More particularly, the invention relates to the use of amidation reaction products derived from oxyalkylene alkyl polyamines and polycarboxyl-containing polymers.
Organic solvent-soluble and water-soluble or -reducible addition interpolymers containing pendent carboxyl groups and pendent amine groups formed from the reaction of a carboxy-containing interpolymer with an alkylenimine are known in the art. U.S. Pat. Nos. 3,719,629, Martin et al, Mar. 6, 1973, and 3,945,963, Levine et al, Mar. 23, 1976 are illustrative of such copolymers. The copolymers of U.S. Pat. No. 3,719,629 are polymeric amine salts. That is, the salt groups are provided by reacting basic groups with an acid. However, this does create problems. For example, the cationic nature of the copolymer prevents it from being readily formulated into a coating composition by blending it with the conventional anionic modifiers normally employed in coating compositions. Additionally, the acid salt cannot be satisfactorily employed as a coating material for unprimed metal substrates since such acid salts usually cause flash rusting. U.S. Pat. No. 3,945,963 describes emulsions of acrylic interpolymers in combination with certain epoxy derived resins. While films formed from the aforedescribed coating systems are satisfactory in many respects, the compositions themselves are difficult to apply due to their relatively short storage stability.
U.S. Pat. No. 4,104,230, Chang et al., Aug. 1, 1978, describes two-package polymeric compositions based upon a polyepoxide and an addition interpolymer. The addition interpolymer contains a polymeric backbone of two or more ethylenically-unsaturated monomers with at least one monomer containing carboxyl groups, said backbone containing pendent amine groups formed by reacting part of the carboxyl groups with an alkylenimine and pendent salt groups formed by reacting part of the carboxyl groups with a base. The disclosed compositions are intended to be dispersed or dissolved in water. Films formed from the disclosed compositions are satisfactory and, additionally, the compositions themselves are storage stable for prolonged periods of time. However, it has been found the alkylenimine used to form the addition interpolymers creates health hazards unless elaborate precautions are taken. The additional processing equipment required when using the alkylenimine necessarily results in a higher product cost.
Amino polymers derived from carboxyl-containing interpolymers wherein an alkylenimine is not used in the processing also are known. For example, U.S. Pat. No. 4,120,839, Emmons et al., Oct. 17, 1978, describes oligomeric polymers based on the reaction product of an alkylene polyamine and low molecular weight addition polymers containing units of alkyl methacrylate and alkyl acrylate. As evident by the disclosure, however, the production of such aminolysis products is difficult due to the lengthy reaction times and high temperatures needed to obtain reasonable yields.
There is a need for amino-containing polymers which can be produced by an economical and safe method. Additionally, the reaction products must be stable and be water-soluble or -reducible. According to the invention herein, amine group-containing reaction products are disclosed. The reaction products can be blended with a crosslinking resin and used in a coating composition.
As used herein, all percents and ratios are by weight unless otherwise indicated.